This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. 9/18/2007 Borderline Personality Disorder (BPD) is a disabling disorder characterized by poor emotion regulation and poor impulse control. The disorder remains notoriously difficult to treat effectively, with many patients responding poorly or partially even to the most widely accepted treatment strategies. For these reasons, developing methods of early identification and prevention of BPD is an urgent priority for the mental health community. This study will focus on early-onset BPD and study older children and adolescents who meet criteria for BPD, in efforts to begin to characterize the underlying neurobiology of the disorder in earlier age populations using magnetic resonance imaging. Aims: (Protocol, Page 3) 1. To examine structural differences in total brain volume, total cerebrum volume, ventricular volume, cortical gray matter, particular areas of the prefrontal cortex including anterior cingulate gyrus, orbital frontal cortex and dorsal lateral prefrontal cortex, and amygdala in adolescents aged 15-18, meeting criteria for BPD compared to normal control adolescents. 2. To investigate whether adolescents with BPD demonstrate similar abnormal findings seen in adult BPD including specific reductions in gray matter volume in ACC (BA 24). Hypotheses: (Protocol, Page 3) 1. Adolescents with BPD will exhibit reductions in ACC but have total brain volumes, ventricular and cerebrum volumes similar to normal control adolescents. 2. Amygdalar volumes in adolescent BPD will not differ from normal control adolescents.